1  # Copyright 2010-2023 Kurt McKee <contactme@kurtmckee.org>
   2  # Copyright 2002-2008 Mark Pilgrim
   3  # All rights reserved.
   4  #
   5  # This file is a part of feedparser.
   6  #
   7  # Redistribution and use in source and binary forms, with or without
   8  # modification, are permitted provided that the following conditions are met:
   9  #
  10  # * Redistributions of source code must retain the above copyright notice,
  11  #   this list of conditions and the following disclaimer.
  12  # * Redistributions in binary form must reproduce the above copyright notice,
  13  #   this list of conditions and the following disclaimer in the documentation
  14  #   and/or other materials provided with the distribution.
  15  #
  16  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 'AS IS'
  17  # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  # ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  20  # LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  21  # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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  23  # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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  25  # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  26  # POSSIBILITY OF SUCH DAMAGE.
  27  
  28  import datetime
  29  
  30  timezone_names = {
  31      'ut': 0, 'gmt': 0, 'z': 0,
  32      'adt': -3, 'ast': -4, 'at': -4,
  33      'edt': -4, 'est': -5, 'et': -5,
  34      'cdt': -5, 'cst': -6, 'ct': -6,
  35      'mdt': -6, 'mst': -7, 'mt': -7,
  36      'pdt': -7, 'pst': -8, 'pt': -8,
  37      'a': -1, 'n': 1,
  38      'm': -12, 'y': 12,
  39      'met': 1, 'mest': 2,
  40  }
  41  day_names = {'mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun'}
  42  months = {
  43      'jan': 1, 'feb': 2, 'mar': 3, 'apr': 4, 'may': 5, 'jun': 6,
  44      'jul': 7, 'aug': 8, 'sep': 9, 'oct': 10, 'nov': 11, 'dec': 12,
  45  }
  46  
  47  
  48  def _parse_date_rfc822(date):
  49      """Parse RFC 822 dates and times
  50      http://tools.ietf.org/html/rfc822#section-5
  51  
  52      There are some formatting differences that are accounted for:
  53      1. Years may be two or four digits.
  54      2. The month and day can be swapped.
  55      3. Additional timezone names are supported.
  56      4. A default time and timezone are assumed if only a date is present.
  57  
  58      :param str date: a date/time string that will be converted to a time tuple
  59      :returns: a UTC time tuple, or None
  60      :rtype: time.struct_time | None
  61      """
  62  
  63      parts = date.lower().split()
  64      if len(parts) < 5:
  65          # Assume that the time and timezone are missing
  66          parts.extend(('00:00:00', '0000'))
  67      # Remove the day name
  68      if parts[0][:3] in day_names:
  69          parts = parts[1:]
  70      if len(parts) < 5:
  71          # If there are still fewer than five parts, there's not enough
  72          # information to interpret this.
  73          return None
  74  
  75      # Handle the day and month name.
  76      month = months.get(parts[1][:3])
  77      try:
  78          day = int(parts[0])
  79      except ValueError:
  80          # Check if the day and month are swapped.
  81          if months.get(parts[0][:3]):
  82              try:
  83                  day = int(parts[1])
  84              except ValueError:
  85                  return None
  86              month = months.get(parts[0][:3])
  87          else:
  88              return None
  89      if not month:
  90          return None
  91  
  92      # Handle the year.
  93      try:
  94          year = int(parts[2])
  95      except ValueError:
  96          return None
  97      # Normalize two-digit years:
  98      # Anything in the 90's is interpreted as 1990 and on.
  99      # Anything 89 or less is interpreted as 2089 or before.
 100      if len(parts[2]) <= 2:
 101          year += (1900, 2000)[year < 90]
 102  
 103      # Handle the time (default to 00:00:00).
 104      time_parts = parts[3].split(':')
 105      time_parts.extend(('0',) * (3 - len(time_parts)))
 106      try:
 107          (hour, minute, second) = [int(i) for i in time_parts]
 108      except ValueError:
 109          return None
 110  
 111      # Handle the timezone information, if any (default to +0000).
 112      # Strip 'Etc/' from the timezone.
 113      if parts[4].startswith('etc/'):
 114          parts[4] = parts[4][4:]
 115      # Normalize timezones that start with 'gmt':
 116      # GMT-05:00 => -0500
 117      # GMT => GMT
 118      if parts[4].startswith('gmt'):
 119          parts[4] = ''.join(parts[4][3:].split(':')) or 'gmt'
 120      # Handle timezones like '-0500', '+0500', and 'EST'
 121      if parts[4] and parts[4][0] in ('-', '+'):
 122          try:
 123              if ':' in parts[4]:
 124                  timezone_hours = int(parts[4][1:3])
 125                  timezone_minutes = int(parts[4][4:])
 126              else:
 127                  timezone_hours = int(parts[4][1:3])
 128                  timezone_minutes = int(parts[4][3:])
 129          except ValueError:
 130              return None
 131          if parts[4].startswith('-'):
 132              timezone_hours *= -1
 133              timezone_minutes *= -1
 134      else:
 135          timezone_hours = timezone_names.get(parts[4], 0)
 136          timezone_minutes = 0
 137  
 138      # Create the datetime object and timezone delta objects
 139      try:
 140          stamp = datetime.datetime(year, month, day, hour, minute, second)
 141      except ValueError:
 142          return None
 143      delta = datetime.timedelta(0, 0, 0, 0, timezone_minutes, timezone_hours)
 144  
 145      # Return the date and timestamp in a UTC 9-tuple
 146      try:
 147          return (stamp - delta).utctimetuple()
 148      except (OverflowError, ValueError):
 149          # IronPython throws ValueErrors instead of OverflowErrors
 150          return None
 151